Climatology of Tornadoes across the Southeast US

First let's look at the yearly, monthly, and hourly distribution of tornadoes for the southeast US (<94W, <36.5N):

Note here the that there is no increase in reporting for tornadoes of F2 or greater intensity, both for the whole year and the cool season. This is consistent through each sub-domain of the southeast, and thus will only be shown here. This provides justification for using only >=F2 tornado reports for other plots in various sections of the climatology.

In the monthly distribution one can see evidence of the secondary peak of tornado reports in November and through February. The time of the secondary peak varies depending on which region of the southeast is examined.

In the hourly distribution of tornadoes (all intensities), one can see that there is a similar distribution of warm and cool season tornadoes diurnally, but that at about 1600 UTC there is a 'changeover'. Between 0100 and 1600 UTC a higher percentage of reports occurs during the cool season, but between 1600 and 0000 UTC (diurnal heating influence), a higher percentage of reports occurs during the warm season. Recall: Cool season = Nov-Mar, Warm season = Apr-Oct.

Lastly, let's examine a Hovmoller diagram of the number of >=F2 tornado reports per hour and month:

Note that there is evidence of the spring maximum of reports near the diurnal heating maximum. Also note that there is evidence of a secondary maximum of reports between 0600 and 1800 UTC during November and December.